Table 3.

Risk of bias evaluation of included studies^a

Study ID	Study design								Study measurements			Statistical analysis			Baseline	Total
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Blake et al. (1995) [20]	√	√	≠	××	×	√	√	2√	√	×	≠	×	√	×√	√	11
Scott et al. (2008) [21]	√	√	≠	√×	√	√	√	3√	√	≠	√	√	√	×√	√	15.5
Pandis et al. (2008) [22]	√	√	≠	√√	×	√	×	√	≠	×	≠	×	√	√≠	√	11
Leite et al. (2012) [17]	√	√	×	√√	×	√	√	2√	√	×	×	×	√	√√	√	13
Liu et al. (2012) [18]	√	√	×	√×	×	√	×	√	√	×	≠	×	√	√√	√	10.5
Jacobs et al. (2014) [23]	√	≠	≠	√√	×	√	×	√	√	×	×	×	√	×√	√	10
Chen et al. (2015) [19]	√	√	≠	√√	×	√	×	√	√	×	×	×	√	×√	√	10.5

^a1 to 15: methodologic criteria in Table 1

√ = 1point; ≠ = 0.5point; × = 0point